In the timing of an engine the valves must be adjusted relative to the angular position of the crankshaft so that the respective valves open and close at the proper time. Many engines include a mark on the flywheel which can be viewed as an aid in timing procedures.
However, some engines do not include a visual marker to indicate the angular position of the flywheel so that the engine can be timed. In such engines the flywheel is enclosed with a bell housing, and the bell housing may include one or two apertures. A bolt can be inserted through one of such apertures to engage a detent or recess in the flywheel. When the bolt engages the detent the flywheel is locked in position and cannot rotate. Then the appropriate adjustments to the valves, etc. can be made to properly time the engine.
The procedure of inserting a bolt through an aperture in the bell housing to lock the flywheel, however, requires two workmen. One must insert the bolt while the other turns the engine until the flywheel is in the proper position so that the detent is in alignment with the bolt.
There has not heretofore been provided a simple, easy to use, and efficient means for aligning the flywheel with the aperture in the bell housing and securing the flywheel against rotational movement during repair procedures.